Morning sickness is one of the major challenges during early pregnancy. Many people may feel anxious about how long it will last and struggle with daily life because of the symptoms. In addition, it can be difficult for others to notice, and many people wonder when and how they should share the news of their pregnancy. Here, we have summarized the causes of morning sickness, along with ways to cope with it more comfortably and the mindset to help you get through this period.

Morning sickness often begins around weeks 5–6 of pregnancy and tends to improve between weeks 12–16 (toward the end of the first trimester). Symptoms vary from person to person—some may have no symptoms at all, while others may experience severe symptoms requiring hospitalization. In some cases, nausea may continue until delivery. Although the exact mechanism of morning sickness has not yet been fully clarified, it is generally thought to occur due to a combination of the following factors.

• Pregnancy hormone (hCG) secretion：
  The hCG hormone secreted during placental formation stimulates the vomiting center in the brain.
• GDF15 (Growth Differentiation Factor 15)：
  Large amounts are secreted from the fetus and placenta, increasing the concentration in the mother’s bloodstream. Recent studies suggest that this acts on the brain’s vomiting center and may trigger morning sickness symptoms.
• Changes in metabolism and blood sugar levels：
  Vitamin deficiencies during pregnancy, as well as changes in metabolism and blood glucose levels, may also contribute.
• Autonomic nervous system imbalance and stress：
  As the body adapts to hormonal and physical changes, disturbances in the autonomic nervous system and mental stress may also play a role.
• Changes in digestive function：
  Increased progesterone can slow gastrointestinal movement, and gas retention may also contribute to discomfort.
• Genetic factors：
  It is said that if a mother or sisters experienced severe morning sickness, there may be a tendency for the symptoms to be more severe as well.

Various factors can cause morning sickness, and even when we understand the reasons, it can still be very difficult to endure. The key to coping well with morning sickness is not to push yourself too hard, but rather to find ways to rest and take it easy whenever possible.

For the time being, do not worry too much about nutritional balance; eat what you can, when you can, and only as much as you can. Cold foods and sour foods tend to be easier to eat. If you experience hunger-related morning sickness, try to avoid an empty stomach by frequently having candy, gum, ice, or similar items in your mouth. It may also be helpful to keep something easy to eat by your bedside. If it is not uncomfortable, wearing a mask may also help block unpleasant smells.

When morning sickness makes you feel unwell, it is perfectly fine to take shortcuts with housework. Try to spend more time lying down and take breaks as needed. If you are working, it may be helpful to consult your workplace about taking breaks. If you are vomiting, try drinking small amounts of sports drinks or oral rehydration solutions containing electrolytes.

Do not push yourself too hard thinking “it is just morning sickness.” If you experience any of the following symptoms, you may have hyperemesis gravidarum, so please promptly visit your obstetrics and gynecology clinic.

• Unable to take in any fluids; no urine output.
• Weight has decreased by 5% or more compared to before pregnancy.
• Vomiting continues throughout the day, or consciousness becomes clouded.

Morning sickness is sometimes said to be a sign that the baby is growing healthily, but when symptoms are severe, please do not endure them. A healthy mother is essential for the baby’s growth as well. Believe that it will eventually come to an end, and spend this time safely within your limits while receiving support from those around you.